Process for manufacturing foils



June 29 1926.

E. CZAPEK ET AL mocass FOR MANUFACTURING FOILS Filg March 20 1924-movable su porting carrier,

- to the carrier, as has been the case in previ- Patented June 29, 1926.

UNITED "STATES EMIL CZAIPEK AND RICHARD WEI NGAIHD, OFIBOMLITZ,

rno'onss non 'mnurac'runme FOILS.

Application filed Karel! 20, 1924, Serial No. 700,672, and in GermanyJune 16, 1922.

This invention relates to foils or films to be obtained from solutionsof cellulose and cellulose compounds, and it refers in particular tonovel means of effecting the co-- tended to provide means whereby in acomparatively short time and by simple manipulations, and in a short waya foil or film may be produced which has been solidified or coagulatedto'such anextent that it may be moved freely in theadditional solidifying or coagulating solutions or baths. In view thereof and in accordancewith my invention the solution of cellulose or of cellulose compounds,of gelatine or the like is applied to the carrier, a rollervor arotatingly fed ribbon, apron, web or the .likefor instance, afterthecarrier has been wetted with the coagulating, solidifying or precipi-'tating agent. The reliminary wetting of the carrier may be e ected forinstance y a separate nozzle by means of which the precipitant issprinkled 'on the carrier. By'

proceedin in this manner the result is accomplishe that thesolidification or precipitation commences at the moment when theliquid-,gelatine or viscose, for instance, after being discharged fromthe ejecting or pouring vessel is made to flow upon the moistenedmovable carrier. The solidification --or co.-

agulation is continued during the further. movement of the carrierthrough the coagulating or precipitating bath, theprecipitation beingeffected from both sides of the liquid coating material. By properlyproportioning the length and velocity of movement ofthe carrier theweb-like pellicle of coa lable material, such as viscose, gelatine or te like possesses such a superiordegree of strength and firmness ascompared with the pellicles precipitated from one side onlg1 that thenew pellicle, being precipitat from the supporting carrier and may beconducted through the remaining precipitating and washing baths, whilein a freely suspended position. In view of the fact that the"precipitation takes place immediately upon the pourin of the solutiononto the any liability of adhesion o the viscose, gelatine or the likefrom both sides, can be easily detachedous processes, is avoided,inasmuch asthe' precipitation begins from the bottom side,

so that there is no further necessity of scraping and cleaningthesupporting ribbon or apron at the point of detachment, nor is thereany necessity of cleaning of the carrier beyond said point.

The detaching of the coagulated ribbon may preferably be effected belowthelevel of the precipitating bath. In this case the wetting of thesupporting carrier by a separate nozzle may be dispensedwith, providedthere is a corresponding freely exposed length of carrier between thepoint of detachment and the level of the precipitating bath. Theaccomplishing of the desired result 'may be facilitated by preferablyheating the supporting carrier within the efiective reach of the pouringvessel, by which,

means the. coagulation or p'reclpitation of the viscose and ofequivalent substances is accelerated -and the process considerablyshortened. This is a point of great importance in view of the lowvelocities of the supporting carrier occurring in this connection. V

The invention 'will be more fully described with reference to theaccompanying drawin .showing'in a diagrammat c manner an by way ofexample the means of carrying out the invention in several forms ofembodiment in Figures 1 to 3. According to Figure 1 a rotatable drum isused as supporting carrier for the solution of cellulose, and Figure 2shows a modification of the arrangement represented .in Figure 1, thecoagulated band being detached from the drum below the level of the bathaccording to Figure 2. Figure 3 illustrates-another form of embodimentof the invention employing a band-like supporting carrier.

In the tank 1,-as shown in Flgure 1 of the and which contains theprecipitating or coagulatin liquid a drum 2 is disosed near one enthereof, which is rotated in the direction of the arrow 5 in anysuitable manner. Upon said drum .2 the film drawing,

producing liquid, such as a solution of viscose for instance, is causedto flow from the receptacle 3' and is applied by means of the ejector-orpourer 4. The nozzle 6 which is preferably inclined opposite to thedirectlon of rotation of the drum 2 is adapted to apply precipitantsupon the drum and 13 mounted between ing bath and the ejector or pourer4, so that the level of the precipitat-- the has already been wettedwith precipitating or coagulating material, when it arrives below theejector t. The detaching of the coa 'ulated or solidified band or'ribbon 7 is e ected above thebath of precipitating liquor by means of aroller 8, and the said ribbon 7 .is then conducted through the a roller20, as shown in dotted lines in Fig- .ure 3. The. drum 12 maybepr'ovided with pxrecipitating bath over the rollers 9 in a eelysuspended condition. In the interior of the drum 2- and within theefiective reach 7 of the pourer or ejector 4 heating pipes 10 may bearranged which are adapted to heat 4 thesupporting carrier, which in thepresent instance is represented by the drum 2. Asa

precipitating bath any of the usual preci itating or coagulatingliquors, such as ch 0- r1de of ammonia, may be used.

j I In the embodiment represented in Figure 2 of the drawing thedetaching of the coagulated ribbon or band 7 from the drum 2 is effectedbelow the level of the precipiv tating bath, in which case theadditional ad'- mission of the precipitating liquor by a nozzle isdispensed with.- The drum 2 becomes wetted with a sufficient coat ofprecipitating liquor within the precipitating bath itself, provided theportion of the periphery of -the drum between the point of detaching theribbon and the level of the precipitating liquor iscorrespondingly,adjusted; so that also in this case the band of'viscoseor the like discharged from the ejector 4 is im- .mediately coagulatedfrom below. Otherwise the arrangement of the different pieces ofapparatus according to Figure Q agrees with that shown in Figure 1 ofthe drawing.

Figure 3 illustrates a form of embodiment. of the principles of theinvention, using an.

a ron or a band-like supporting carrier. he apron 11 of suitablematerial is conducted in this case in an. inclinedpositi'on over the twodrums 12 and 13.' Atthe po= likewise an immediate coagulation isaccomplished'. The coagulated ribbon is detached below .the level ofthe-precipitating bath sition of the dru-m 13 disposed at a lower.

level precipitating agent is squirted upon the carrier apron from thenozzle 14, while the pourin out of the viscose or the like from the eector 15 is efl'ectedat the position of the drum 12 at a higher level.The

carrier apron 11 is moving in the direction of the arrow 16, and isalready wetted with. the precipitant when it arrives below the.

ejector or pourer- 15, so that in this case from the carrier apron 11 bymeans of "1.8-

heating pipes 17 within the operative reach of the ejector 15 with theeffect of ass1sting the coagulation according to the process.

The drums 12, 13 are operated in the usual manner; The invention hasbeen shown and described in its broad aspects only, and it should beunderstood thatiitis not restricted to the particular means hereinshown, but it is susceptible of other modifications arid changes tobetter adaptit to'e'xisting condi tions and to the convenience-of theuser, and within the scope of the claiins hereunto appended. Weclaiin:--- I 1, The method of manufacturing foils from cellulosicsolutions,, such as ,viscose,

the extent of treatment with the pre'cipi-' tating liquid beingregulated to [thoroughly precipitate the foil. 2.- Process for thecontinuous manufac-' ture of foils from cellulosic solutions, such asviscose, capable of being precipitated, Which-comprises causing anenlesscarrier to progress with a portion of its travel through such aliquid as will quickly precipitate the cellulosic solution, whereby theI, .carrieris wetted, flowing said cellulosic solution on the wettedcarrierto form a foil, and passing the foil supported by the carrierdown through the precipitating. liquid, the velocity of the carrier'andthe -extent of treatment with the precipitating liquid being regulatedthe foil.

In testimony names to this specification.. i 4 I DR.'EMHJ.GZAPEK-RICHARD W-EINGANDY 7 s0 capable of being precipitated, which com? tothoroughly precipitate whereof we have signed our V

